A cylindrical piece of wood is 20 decimetres long. After sawing the cross section of 5 decimeters, the surface area of the remaining wood is 94.2 square decimeters smaller than that of the original wood. What is the original volume of this wood?
Three people buy soda to drink. According to the regulations, three empty bottles can be exchanged for one soda. If these three people buy 10 bottles of soda, how many bottles of soda will they drink?
4 Calculate the volume of the figure below. First of all, describe this part: this part is a steel pipe with an inner diameter of 20 cm, a wall thickness of 5 cm and a height of 34 cm; Below is a cuboid, 68 cm long, 50 cm wide and 16 cm high. Find the volume of this part.
There is a wooden cube, and its side length is 4 decimeters. Make this piece of wood into the largest cylinder. What is the volume of this cylinder?
The circumference of the bottom of the cone is 3 1, 4 cm, and the height is 9 cm. How many cubic centimeters is its volume?
The bottom area of a cone is equal to the bottom area of a cylinder. It is known that the volume ratio of cone to cylinder is 1: 6, the height of cone is 4 or 8 cm, and the height of cylinder is how many cm?
The base diameter of cone and cylinder is 16 cm, the height of cone is 17 cm, and the height of cylinder is 4 cm. Find the sum of their volumes.
Team 9 A and Team B cooperated on a project, which was completed in 24 days. Now Team A has done it for six days, and then Team B has done it for four days, completing one-fifth of the project. How many days does it take each team to complete the task alone?
10 The height of a cylindrical container with a bottom radius of 6 cm is equal to the height of a conical container with a bottom radius of 9 cm. Now, the conical container is filled with water and poured into the cylinder, and the water depth is lower than that of the container 1.5 cm. How many centimeters is the cylindrical container?
1 1 If a car travels at a speed of 45 kilometers per hour from A to B, it will arrive 0.5 hour late. If it wants to drive at a speed of 50 kilometers per hour, it can arrive 0.5 hour earlier. Find the distance between a and b and the original planned driving time.
12, Xiao Ming read a story book with 120 pages. On which page should he start reading the book on the first day?
13, rectangular swimming pool, 50 meters long, 30 meters wide and 2 meters deep, with a layer of cement at the bottom and around. If you use 10 kg cement per square meter, will 20 tons of cement be enough?
14. Fold a rope in half, then in half, then in half. How much does each paragraph take up at this time?
/kloc-Class 0/5 and Class 6 (1) have 40 people in total. Among them, some students joined the math interest group, some students joined the reading interest group, and how many students in Class 6 (1) joined two interest groups at the same time?
16, three students jump rope 1 minute. B jumps twice as often as A, and C jumps twice as often as A. Who jumps the most among these three people? Who jumps the least? (explained by calculation)
17, the distance between the two places is 300 kilometers. A car has traveled 80 kilometers from A to B. How many kilometers does it take?
18. Xiaoli's family has a bag of 50 kg of rice. She ate 15 kg in the first week and the rest in the second week. How many Jin did she eat in the second week?
19, Master Wang's home has a rectangular goldfish bowl, which is 5 cm long, 4 cm wide and 3 cm high. The glass on the left and back of this goldfish bowl is broken. Master Wang needs two more pieces of glass, at least how many square decimeters of glass? There is 2.5 meters high water in the goldfish bowl. How many kilograms of water does it contain? (1 water weight of cubic decimeter 1 kg)
20. A ball falls from a height of 40 meters, and the height it bounces up after touching the ground every time is the height of falling. What is the height of the bouncing ball after the second fall?
2 1 a car travels 72 kilometers per hour, and a small car travels 4 kilometers less than driving. How many kilometers does Xiao Fang ride a bike every hour?
For a book, the ratio of read to unread is 1: 5, and 30 pages are being read. The ratio of read to unread is 3: 5. How many pages are there in this book?
Party A and Party B set out from M.N and walked to each other at the same time. When they set off, their speed ratio was 3: 2. After the first meeting, the speed of Party A increased by 20/ 100, and the speed of Party B increased by 30/ 100. Zhey, in this way, when Party A arrives in N, Party B is still 100 away from M.
24 Add () grams of water to obtain 80 grams of sugar water with a concentration of 10%.
A commodity is priced at a profit of 20%, and then sold at a discount of 88%, * * * gains a profit, 84 yuan. The cost of this commodity is () yuan.
26 A container contains 150g of 4% salt water, and B container contains a few grams of salt water with a certain concentration. Take it out of B.
450 grams of salt water, put it in A and mix it into 8.2% salt water. Then pour water into container B to make it as much as the salt water in container A. Now the concentration of salt water in container B is 1. 12%. How many grams of salt water are there in container B? What is the percentage of concentration?
27. A bottle of drinks costs 80 cents. After drinking, you can change one of the three bottles. Xiaoming has money from 35 yuan. How many bottles of drinks did he drink?
28. When the ship is stationary, it travels per minute 100 m, and it travels more in countercurrent than in downstream 10 m.. Excuse me, how many meters do you walk downstream in still water every hour?
29. There are two goldfish bowls. If you take out 15 from the first tank and put it in the second tank, the goldfish in the second tank is just 5/7 of the first tank. It is known that there are 35 goldfish in the second tank. How many goldfish are there in the first fish tank?
30. The minute hand of the wall clock is 20 cm long. After 45 minutes, how many centimeters did the tip of this minute hand walk?
3 1. After a period of training, Xiao Ming shortened the running time of 5000m by one tenth, so he
How much faster than before?
32. The difference between A and B is 9, and one sixth of A and one quarter of B are equal. What is the sum of A and B? 33. The natural number with only 10 divisors in100 is ().
The bookcase is divided into upper and lower floors. The ratio of the number of books in the upper and lower floors is 10: 7, and 1/5 (that is, one fifth) is taken out from the upper floor. After the bottom floor is full of six books, there are as many books on the top and bottom floors now. How many books are there upstairs?
A cylinder with a bottom radius of 5cm is vertically cut into two semi-cylinders along a diameter at the bottom, and the surface of each part is 412.6cm2. What is the height of this cylinder?
In Xiaohua's mid-term exam, the average score of Chinese mathematics is 86, the total score of mathematical English is 170, and the average score of Chinese English is 90. What is the average score of three courses?
There is a knowledge test with 20 questions. Answer a question correctly and get 5 points; If you type a wrong question, you will get 3 points; If you didn't answer 0, Li Bing got 87 points. He answered several questions wrong.